Safety belt buckle for vehicles

ABSTRACT

A safety belt buckle comprises a latch portion including two parallel plates, locking elements in the form of rolls, members for stopping the rolls in latched and unlatched positions of the buckle in the form of a wedge and plate-like pushers respectively, a member for unlatching the buckle fashioned as a button, and a catch part in the form of a prong having a slot for receiving the safety belt and a portion insertable into the shell. The plates of the shell have slots for the rolls to move therein and slots wherethrough the wedge is connected to the button.

FIELD OF THE INVENTION

This invention relates generally to passive safety systems of vehicles,and more particularly to a construction of locks or buckles for vehiclesafety belts.

The safety belt buckle according to the invention can be used mostsuccessfully for protecting vehicle drivers and passengers from roadaccidents by supporting the weight of wearers under impacts.

The proposed buckle can also be used with other types of safety beltsemployed, for example, in aviation, by steeplejacks, and elswhere.

BACKGROUND ART

Rule 16 of the ECE UN International Regulations prescribes verystringent requirements to be met by vehicle safety belts locks.Particularly, the lock must withstand a load of over 1500 kgf andfunction satisfactorily; it should further withstand no less than 5000latch-unlatch cycles without its strength being affected; both lockparts, male and female, must interlock automatically withoutintermediate steps of incomplete latching; the minimal pressure forceexertable on the release button for unlatching the lock under a 30.6 kgfload must not exceed 6.1 kgf, etc.

There is known a safety belt lock or buckle for vehicles comprising twointerlatching parts, particularly a female part and a male part. Thefemale part includes a bar attachable to the vehicle body, and a shellsecured in a protective housing, connected to the bar and made up of twoparallel power plates. The female part also comprises locking elementsmovably arranged in the shell and fashioned as rolls, spring-biasedmembers for stopping the rolls in the latched and unlatched positions ofthe buckle, and a member for unlatching the buckle in the form of apressure button slidable along the shell.

The male part of the buckle has the form of a prong with an eye or slotfor receiving the safety belt, this prong having a flat portioninsertable into the shell and having at its end symmetrical shapedprojections for engagement with the rolls in the shell (cf., e.g.,Laid-Open Application of West Germany No. 2,915,246; Cl. A 44 B 11/14).

In the aforedescribed prior art safety belt buckle the power plates ofthe shell are provided with slots for the rolls to movably accommodatetherein and recesses for the locking means in the form of balls. Themember for stopping the rolls in latched position of the buckle ismounted on the shell and fashioned as a spring-loaded ring elementembracing the shell and having inner recesses for the rolls and balls.

In the known technical solution, for rendering the buckle reliable underheavy loads, including those tending to twist the shell, the member forstopping the rolls in the form of a ring embracing the shell must besufficiently strong, and therefore this ring is fabricated from metal tooffer greater toughness. However, the provision of high-precisionrecesses for receiving the rolls and balls is associated with certainmanufacturing difficulties. On the other hand, the heavy bulk of thebuckle necessitates its locking by balls, which makes the overallconstruction complicated.

In addition, because the ring is capable of movement relative to theentire cross-section of the shell, the protective housing of the bucklealso becomes overcomplicated, since accidental jamming of the ringbetween the shell and the housing during buckle use must be prevented.Further, the aforedisclosed technical solution calls for increase in thecross-sectional dimensions of the buckle.

SUMMARY OF THE INVENTION

This invention is directed toward the provision of a safety belt bucklefor vehicles having such structural arrangement of a shell and means forstopping rollers in latched and unlatched positions of the buckle as toimprove the reliability of the buckle and simplify its construction.

The aims of the invention are attained by that in a safety belt bucklefor vehicles comprising two interlocking parts, particularly a latchpart which includes a shell made up of two parallel power platesdisposed inside a housing and connected to a bar attachable to a vehiclebody, locking elements in the form of rolls movably arranged in theshell, spring-biased members for stopping the rolls in latched andunlatched positions of the buckle, and means for unlatching the bucklein the form of a push button slidable along the shell, as well as acatch part in the form of a prong having a slot to receive the belt andfurther having a flat portion insertable into the shell and provided atits end with symmetrical lugs engageable with the rolls, according tothe invention, provided in the plates transversely of the central axisof the shell are mutually coaxial shaped slots adapted to receive therolls, whereas arranged in line with the central axis of the shell aremutually coaxial slots, the member for stopping the rolls in the latchedposition of the buckle having the form of a wedge rigidly connectedthrough the slots made in the plates of the shell to the push button andhaving a tapered end facing the rolls, the member for stopping the rollsin unlatched position of the buckle having the form of plate-likepushers secured edgewise of the plates of the shell for engagement withthe end face of the portion of the prong insertable into the shell andwith the rolls, the lugs of the insertable portion of the prong beingdefined by a shaped recess open on its end to face each other.

Thanks to the aforedescribed arrangement, the rolls are stopped in thelatched position of the buckle by forcing the wedge between the rollsand by means of the shaped recess provided in the insertable portion ofthe prong to embrace the rolls, whereby the use of a massive ringembracing the shell becomes unnecessary. This in turn considerablysimplifies the device structurally and makes the parts of the buckleeasier to fabricate. At the same time, the overall dimensions of thebuckle are reduced accompanied by an improvement in its reliability,because accidental jamming of the wedge is practically impossible.

Preferably, the front ends of the shell plates are bonded together by arivet, whereas the shaped recess of the insertable portion of the pronghas an indentation adapted to embrace the inner portion of the rivet inthe latched position of the buckle.

The above arrangement improves the reliability of the buckle, sincetwisting forces exerted on the latched buckle fail to cause damage ofthe buckle and are not transmitted to the buckle housing enclosing theshell.

Advisably, the width of the clearance between the lugs of the insertableportion of the prong is equal to the sum of the diameters of the rolls,whereas the width of the inner portion of the shaped recess preferablyequals the sum of diameters of the rolls and the width of the wedge.

This renders a greater strength to the buckle and ensures that the partsof the buckle operate more accurately, since the clearances between therolls and the working surfaces of the recess in the insertable portionof the prong and wedge are substantially reduced.

Further, it is advantageous to make the shaped slots in the power platesof the shell arcuate. In case of such an arrangement, optimizeddistribution of loads exertable on the buckle elements is attained toensure that the prescribed minimum of pressure force required foractuating the button for unlatching the buckle under tensile loads isguaranteed.

For more accurate guiding of the portion of the prong insertable intothe shell, the housing is provided in its interior with elongated ribsconfining the shell on two sides in terms of width of the insertableportion of the prong. As is obvious from the foregoing, the arrangementjust described does not affect the strength of the housing normallyfabricated from a plastic material, since high twisting loads exertableon the buckle are countered by the shell thanks to the provision of therivet connecting the front ends of its power plates and the indentationmade in the shaped recess of the insertable portion of the prong andembracing the rivet.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference toa preferred embodiment thereof taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a plan view of a safety belt buckle according to the inventionin latched position with the front half of the housing removed, a pressbutton for unlatching the buckle and one of the power plates of theshell not being shown;

FIG. 2 illustrates a portion of the buckle of FIG. 1 in unlatchedposition;

FIG. 3 is a section taken along the line III--III in FIG. 1;

FIG. 4 is a section taken along the line IV--IV in FIG. 1; and

FIG. 5 is a section taken along the line V--V in FIG. 1.

BEST MODE OF CARRYING OUT THE INVENTION

The proposed safety seat belt buckle for vehicles illustrated in FIGS. 1and 2 comprises two parts indicated in FIG. 1 by 1 and 2, respectively,which can be latched to each other when they are brought together, thesetwo parts being referred to hereinafter as latch part 1 and catch part2.

The latch part 1 includes a shell 3 disposed inside a housing 4 to beconnected to a bar 5 having a protective-decorative plastic coating 6applied thereto and secured to a vehicle body (not shown).

The shell 3 comprises two parallel power plates 7 (FIG. 3) and 8 clampedtogether at their end portions by a rivet 9.

The latch part 1 of the buckle also includes locking elements in theform of rolls 10 (FIG. 1) and 11 movably secured in the shell 3, amember 12 for stopping the rolls 10 and 11 in latched position of thebuckle and a member 12' (FIG. 2) for stopping the rolls 10 and 11 inunlatched position of the buckle, these members 12 and 12' being mountedon springs 13 (FIG. 4) and 14 (FIG. 5), respectively, as well as a meansfor unlatching the buckle in the form of a press button 15 (FIG. 3)slidable along the central axis of the shell 3.

The catch part 2 of the buckle is fashioned as a prong 16 (FIG. 1)having a slot 17 to receive the safety belt (not shown) and having asubstantially flat portion 18 insertable into the shell 3 and providedat its end with symmetrically arranged lugs 19 and 20 for engagementwith the rolls 10 and 11 and with the power plates 7 and 8.

According to one feature of the invention, provided centrally of thefront portion of each of the plates 7 and 8 are shaped slots 21 and 21'for receiving the rolls 10 and 11. These slots 21 (FIG. 2) and 21' arecoaxial and run transversely of the central axis of the shell 3. Inaddition, the power plates 7 and 8 have coaxial slots 22 and 22'arranged in line with the central axis of the shell 3.

The member 12 for stopping the rolls 10 and 11 in a locked position ofthe buckle is fashioned as a substantially flat wedge 23 (FIG. 1)rigidly connected to the press button 15 through the slots 22 and 22' inthe power plates 7 and 8. The rigid connection of the wedge 23 with thebutton 15 is made possible thanks to a projection (not shown) providedon the button 15. The working portion of the wedge 23 has an end 24tapering toward the rolls 10 and 11, whereas the central portion of theflat wedge 23 has an elongated hole 25. Side faces of the wedge 23 maybe either parallel or may taper slightly toward the working portionthereof.

The member 12' (FIG. 2) for stopping the rolls 10 and 11 in unlockedposition of the buckle has the form of plate-like pushing elements 26and 27 arranged at the sides of the power plates 7 and 8 of the shell 3and engageable with the end face of the portion 18 of the prong 16insertable into the shell 3 and with the rolls 10 and 11. These pushers26 and 27 have tail pieces 28 (FIG. 5) and 29 having projections 30 and31, respectively, which carry springs 14 with ends thereof thrustingagainst the projections 30 and 31.

The lugs 19 and 20 on the portion 18 of the prong 16 insertable into theshell 3 are defined by a shaped recess 32 (FIG. 1) open on the end ofthis portion 18, these lugs 19 and 20 are opposite to each other andspaced from each other at a distance l₁ inside the recess 32. The lugs19 and 20 have smoothly rounded angles.

The front ends of the power plates 7 and 8 are joined together by aspaced rivet 33, whereas in order to embrace its inner part in thelocked position of the buckle, there is provided an indentation 34 inthe shaped recess 32, this indentation having an inner locking radius R₁corresponding to the curvature radius of the inner part of the rivet 33.

The distance l₁ between the lugs 19 and 20 of the insertable portion 18of the prong 16 equals to the sum of diameters d of rolls 10 and 11,whereas the width l₂ of the inner section of the shaped recess 32 equalsto the sum of diameters d of the rolls 10 and 11 and the width t of thewedge 23.

The shaped slots 21 and 21' provided in the plates 7 and 8 of the shell3 are arcuate. The lugs 19 and 20 on the insertable portion 18 of theprong 16 mates with the wider portion of the shaped recess 32 through acurvature having a radius R₂ equal to the curvature radii of the rolls10 and 11.

The shell is enclosed by a plastic housing 4 made up of a rear section35 (FIG. 4) and a front section 36 joined together such as by ultrasonicwelding. The rear section or half 35 of the housing 4 has longitudinallyextending ribs 37 and 38 confining the front or latch part of the shell3 on both sides and functioning as guide walls for accurately receivingthe insertable portion 18 of the prong 16 into the space between thepower plates 7 and 8 of the shell 3. An inlet hole 39 (FIG. 3) flaringoutwardly is provided on the end face of the latch part l of the bucketto facilitate the reception of the prong 16 by the shell 3.

The slots 21 and 21' are rounded at their ends at a radius R₂corresponding to the curvature radii of the rolls 10 and 11, a radius R₃of the curvature of the arches of the slots 21 and 21' being preferablywithin three to seven times the diameter d of the rolls 10, 11. Thewidth of the slots 21 and 21' is comparable with the diameter d of therolls 10, 11, although a small clearance is preferably provided toensure that these rolls 10 and 11 could freely move to remainperpendicular to the planes of the power plates 7 and 8.

The other ends of the springs 14 bear on shelves 40 made inside the rearhalf 35 of the housing 4. Ends 41 of the plate-like pushers 26 and 27have shaped configuration to cooperate with the rolls 10 and 11 and withthe end face of the prong 16. Provided between the front half 36 of thehousing 4 and shell 3 is a cavity 42 (FIG. 4) in which there is mountedunlatching means or push button 15 partially extending through a port 43(FIG. 3) made in the front half 36 of the housing 4. Wall 44 of thebutton 15 adjoins the shell 3 and has provided thereon a lug 45extending through the slots 22 and 22' in the plates 7 and 8 and throughthe elongated hole 25 in the wedge 23. In this manner the push button 15is rigidly connected to the wedge 23. In a space between the wall 44 ofthe button 15 and the front half 36 of the housing 4 the spring 13(FIGS. 3 and 4) is disposed to be confined between longitudinallyextending ribs 46 and 47 provided partially on the wall 44 and partiallyinside the front half 36 of the housing 4. The spring 13 bears by one ofits end on a cross rib 48 of the button 15 and by the other end on ashelf 49 provided in the interior of the front half 36 of the housing 4.The distance between inner side edges 50 of the plate-like pushers 26and 27 is accordingly l₁ to correspond to the sum of diameters d of therolls 10 and 11.

The outer part of the prong 16 is coated with a plastic layer 51 (FIG.3), this being necessary to prevent damage to a safety belt (not shown)when it is passed through the slot 17 thereby protecting the safety beltfrom sharp edges of the metal of the prong 16.

The proposed safety belt buckle operates in the following manner.

When unlocked, the plate-like pushers 26 and 27 (FIG. 2) rest in theirextreme projected position to hold by their inner side edges 50 therollers 10 and 11 in the central portion of the slots 21 and 21',whereas the wedge 23 is pressed by its tapered end 24 against the tworolls 10 and 11. Therewith, the push button 15 occupies its extremedepressed position for its spring 13 to be fully compressed.

During latching, the insertable portion 18 of the prong 16 enters theshell 3, and its end faces are brought into contact with the respectiveend faces 41 of the plate-like pushers 26 and 27. A further travel ofthe portion 18 insertable inside the shell 3 is guided by the ribs 37and 38 of the rear half 35 of the housing 4, whereby the springs 14 ofthe pushers 26 and 27 are compressed.

At the point when the rolls 10 and 11 pass through the lugs 19 and 20 ofthe portion 18 of the prong 16 the distance l₁ between which, as hasbeen stated above, corresponds to the sum of diameters d of the rolls 10and 11, the tapered end 24 of the working portion of the wedge 23 actsby its tapers 51 and the spring 13 to push the rolls 10 and 11 apart totheir extreme positions in the slots 21 and 21' of the power plates 7and 8. Therefore, the rolls 10 and 11 tend to occupy corners 52 of theshaped recess 32 in the insertable portion 18, whereas the wedge 23travels further forward to lock the rolls 10 and 11. In consequence, thepush button 15 is drawn in a direction opposite to one indicated by thearrow A in FIG. 3 to occupy its extreme raised position. Also, in thecourse of latching, the indentation 34 of the recess 32 of theinsertable portion of the prong 16 tends to embrace the mid-portion ofthe spaced rivet 33 (FIG. 1). One advantage of this action resides inthat the prong 16 is held securely in the shell 3 against twisting loadsin a plane parallel with the power plates 7 and 8, whereby the ribs 37and 38 confining the sides of the shell 3 are not subjected to excessiveloads. In the thus latched position the safety belt buckle according tothe invention is capable of withstanding high tensile loads and is notsusceptible to various lateral impacts.

In order to unlatch the buckle, it is necessary to apply a force ofpressure to the push button 15 as indicated by the arrow A to therebycompress the spring 13. In consequence, the lug 45 on the wall 44 of thepush button 15 acts on the wedge 23 to shift it from the position itoccupies between the rolls 10 and 11.

When the working portion of the wedge 23 retracts completely, the lugs19 and 20 having rounded corners 52, act by the pressure produced by thesprings 14 of the plate-like pushers 26 and 27 to move the rolls 10 and11 about the upper arc of the radius R₃ of the slots 21 and 21' untilthey are drawn together in the central portion of these slots. Thepushers 26 and 27 then eject the thus released prong 16 from the shell3. Concurrently, while cooperating by the ends 41 and side walls 50 withthe rolls 10 and 11, the plate-like pushers 26 and 27 project to theirupmost position to stop the rolls 10 and 11 in the unlatched position ofthe buckle.

INDUSTRIAL APPLICABILITY

The safety belt buckle embodying the present invention features highreliability and extended service life, which ensures passive vehiclesafety for the driver and other wearers of safety belts using theproposed buckle.

The safety belt buckle is sufficiently small in size and easy toconstruct. Mass production of the proposed buckle is amenable tomechanization and automation.

In view of the foregoing, the proposed buckle is less costly tofabricate than most prior art constructions of fastening devices used invehicle safety belts.

What is claimed is:
 1. A safety belt buckle for vehicles, comprisingtwointerlocking parts, a latch part and a catch part, said latch partincluding a shell formed by two substantially parallel plates disposedinside a housing and connected to a bar secured to a vehicle body,locking elements in the form of rolls movably disposed in said shell,spring-biased members for stopping said rolls in both latched andunlatched positions of the buckle, and a member for unlatching thebuckle in the form of a push-button and being slidable along said shell,said catch part in the form of a prong having a slot to receive the beltand additionally having a substantially flat portion insertable intosaid shell and provided at an end thereof with substantially symmetricallugs engageable with said rolls, wherein substantially coaxial slotsextending substantially transversely with respect to a central axis ofsaid shell, are provided in said plates, said slots adapted to receivesaid rolls, substantially coaxial slots which extend substantially inline with said central axis of said shell, are also provided in saidplates, said member for stopping said rolls in the latched position ofthe buckle being in the form of a wedge rigidly connected through saidaxially-extending slots with said push button and having a tapered endfacing said rolls, said member for stopping said rolls in the unlatchedposition of the buckle, having the form of plate-like pushing elementssituated at sides of said plates forming said shell and for engagementwith an end face of said portion of said prong insertable into saidshell and with said rolls, and wherein said prong additionally comprisesa shaped recess open at the end face of said insertable portion, saidrecess defining said lugs of said insertable portion of said prong, suchthat said lugs face one another.
 2. The buckle of claim 1, additionallycomprisinga rivet joining front ends of said plates of said shelltogether, said shaped recess of said prong having an indentation adaptedto embrace an inner portion of said rivet in the latched position of thebuckle.
 3. The buckle of claim 1, whereina distance between said lugs ofsaid insertable portion of said prong is substantially equal to a sum ofdiameters of said rolls, and a width of an inner portion of said shapedrecess of said prong is substantially equal to a sum of the diameters ofsaid rolls and a width of said wedge.
 4. The buckle of claim 1, whereinsaid transversely-extending slots in said plates are substantiallyarcuate.
 5. The buckle of claim 1, wherein the housing of the bucklecomprisesribs substantially longitudinally extending along an interiorthereof, confining said shell on two sides with respect to a width ofsaid insertable portion of said prong.
 6. The buckle of claim 1,whereinsaid recess comprises an interior portion being wider than theopen portion thereof at the end face of said insertable portion.
 7. Thebuckle of claim 2, whereinsaid inner portion of said rivet comprises aradius of curvature substantially equal to a radius of curvature of saidindentation.
 8. The buckle of claim 1, wherein saidtransversely-extending slots are rounded at ends thereof with a radiusof curvature substantially equal to a radius of said rolls.
 9. Thebuckle of claim 6, wherein said lugs mate with said insertable portionof said prongs at said wide portion of said recess, through a curvaturehaving a radius substantially equal to a radius of said rolls.
 10. Thebuckle of claim 5, wherein said transversely-extending slots comprisearadius of curvature about 3 to 7 times a diameter of said rolls.
 11. Thebuckle of claim 10, whereinsaid transversely-extending slots each have awidth slightly greater than a diameter of said rolls.
 12. The buckle ofclaim 1, additionally comprisinga second rivet clamping said plates ofsaid shell together, said second rivet being situated on a side of saidrolls opposite said first rivet.
 13. The buckle of claim 3, whereinthewidth of said wedge is slightly less than the distance between saidlugs.
 14. The buckle of claim 3, whereina distance between inner sideedges of said plate-like pushing elements is substantially equal to thesum of the diameters of said rolls.
 15. The buckle of claim 1,additionally comprisinga pair of springs, each spring connected at oneend thereof with a respective plate-like pushing element, and at theopposite end thereof with the housing, said springs biasing saidplate-like members towards said rolls, and a third spring engaged at oneend thereof with said push-button and at an opposite end thereof withthe housing, said third spring biasing said push-button in a directionout of the housing.
 16. The buckle of claim 15, whereinsaid push-buttonand said housing comprise respective substantiallylongitudinally-extending ribs for confining said third springtherebetween, said button comprises a cross-rib upon which the end ofsaid third spring bears, and the housing comprises a shelf upon whichthe opposite end of the said third spring bears.